This summer, Dennis Washington completed a nearly four year, estimated $200 million renovation on his latest yacht, the breathtaking 332-foot Attessa IV; it's the 10th yacht he's fixed up over the years. Another recently finished project is the $30 million construction of a middle school campus at the Washington Family Ranch, the Oregon camp he donated to Young Life, a Christian youth organization. Altogether he's spent $60 million on the camp. Washington made his luck and fortune "the old fashioned way," in businesses like construction, railways and mining. His Washington Co. controls a copper mine in Butte, a tugboat and barge business in Vancouver, and Montana Rail Link. The child of divorced parents, he had a tough start, "I went to seven grade schools. I was a god damn cripple," he says, referring to his childhood bout with polio, from which he fully recovered. He eventually settled down in Montana with his grandparents. After working for his uncle's construction company he went out on his own and got a $30,000 loan from a local Caterpillar dealer to start his own highway construction firm. Though he doesn't spend much time in the office these days, Washington still gets updates at least every other day and signs off on any transaction. "I know what's going on, so I can stop and raise hell," he says.

Cargill and Liebmann are two of seven relatives on the Forbes 400 who hold a combined 88 percent of Cargill, the largest private company in the U.S. Pritzker inherited her fortune from her grandfather, A.N. Pritzker, who helped build the Hyatt hotel chain. She's also a Tibetan Buddhist and psychotherapist.